Re: Hidden causes of continual weight gain?
Even though they were normal, was your TSH above 2.0? That could indicate a thyroid issue, even if it was considered within normal range. Were Free-T3 and Free-T4 both normal?
Are you on any medications? I've heard that birth control or antidepressants could cause continual weight gain.
You haven't changed your diet, but what does your typical day's menu look like? Metabolism does slow down start in one's mid-20's and really starts to become noticeable in the 30's. Could you be getting too many "extra" calories, such as adding sugar to your coffee every day, mayo instead of mustard on sandwiches, etc?
What about sleep-- do you get 8 hours each night? Do you feel pretty rested in the a.m.? Do you stay awake "unusual" hours, such as graveyard shift?